Which one is the weakest base?

In the chemical reaction given above,$A$ and $B$ respectively are:

Identify the compound from the following having the lowest boiling point.

The order of basicity of the compounds is

In the given reaction,identify the reagent $A$:
$4-nitro-3-bromobenzenediazonium \ chloride \xrightarrow{A} 1-bromo-3-nitrobenzene$

$A$ solution contains $1 \ g \ mol$ each of $p-$toluene diazonium chloride and $p-$nitrophenyl diazonium chloride. To this,$1 \ g \ mol$ of alkaline solution of phenol is added. Predict the major product and explain your answer.